For me, Jennings has some serious technical issues to sort out - get him out and get him worked on!
Hameed needs to get some more experience and really toughen up - the Aussies will chew him up and give him serious stick! He needs time!!
I say get Stoneman in. I realise one or two people have said that the Windies haven't got the same bowling attack as the Aussies, but you can watch a batsman and tell if he has a decent technique or not! If they can't look at a batsman and tell what needs working on within 10 minutes, then they shouldn't be anywhere near the England Coaching Team!! I would look at......
Cook
Stoneman
Westley
Root
Hales
Stokes
Bairstow
Ali
Woakes
Broad
Anderson
If anyone has a niggle or needs a rest then bring someone else in! The thought of Hales on decent form slotting in at 5 is a little exciting with Stokes, Bairstow and Ali to follow!!
Thinking ahead to Winter, I would also take Hameed, Ballance, Robson, TRJ, Ball, Woods, Crane, Buttler. Unsure how many squad players we normally take to the Ashes?